Emerald Energy
From Dragon Mania Legends (DML) Wiki
Emerald Energy is the energy used in Emerald Wars, a Clan Event, each time a battle is fought. Every player has 6
at maximum as a base amount, and attacking a mine costs 1 Emerald Energy. If a Trainer's Dragon participates in a battle for controlling an emerald mine, it needs to rest for a certain amount of time before it can fight again (it can be used outside the event while resting). The resting time can be skipped with Revitalization Tokens earned completing regular Clan Quests.
Emerald Energy automatically regenerates at 1 every 60 minutes, up to the maximum base amount. It can also be recovered through Revitalization Tokens (at the cost of 1 Revitalization Token per energy), through Gems (at the cost of 5 Gems per energy), or through leveling up. Both methods fully replenish the energy, and there is no option of choosing the amount of energy desired for replenishing when using Gems or Revitalization Tokens. The only way to replenish the Emerald Energy in smaller amounts is to use small amounts at a time, and then a Trainer can replenish the amount remaining to maximum. The Emerald Energy can be refilled by pressing the + button in the main screen of Emerald Wars, and by trying to engage a battle without any energy left (which will bring up the refill screen from where the energy can be refilled either with Revitalization Tokens or Gems).
See Battle Energy for more information